The present technology generally relates to a secondary battery including an electrolyte layer including an electrolytic solution and a polymer compound, and a battery pack, an electric vehicle, an electric power storage system, an electric power tool, and an electronic apparatus that use the secondary battery.
Various electronic apparatuses such as a mobile phone and a personal digital assistant (PDA) have been widely used, and it has been demanded to reduce the sizes and weights of the electronic apparatuses and to achieve their long life. Accordingly, as an electric power source for the electronic apparatuses, a battery, in particular, a small and light-weight secondary battery capable of providing high energy density has been developed.
It has been considered to apply a secondary battery not only to the foregoing electronic apparatuses, but also to other applications. Examples of other applications include a battery pack detachably mounted in electronic apparatuses or the like, an electric vehicle such as an electric automobile, an electric power storage system such as a home electric power server, and an electric power tool such as an electric drill.
The secondary battery includes an electrolytic solution together with a positive electrode and a negative electrode. The electrolytic solution is mounted in the secondary battery in a state of being impregnated in a separator, and other than this, the electrolytic solution is mounted in the secondary battery in a state of being held by a polymer compound. The latter secondary battery includes an electrolyte layer that is a so-called gel electrolyte. In the secondary battery including this electrolyte layer, leakage of the electrolytic solution is prevented.
A configuration of the polymer compound contained in the electrolyte layer may largely influence battery characteristics of the secondary battery, which has led to various considerations on the configuration of the polymer compound.